Anchors for tubular strings



March 12, 1,963 .1. R. BAKER ETAL ANCHORS FOR TUBULAR swarms Filed March18, 1960 2 Sheets-Sheet l JOHN B- BAKER JUL/0N D. KEITHHHN INVENTORS.

flrroeusys.

March 12, 1963 J. R. BAKER ETAL ANCHORS FOR TUBULAR STRINGS I FiledMarch 18, 1960 2 Sheets-Sheet 2 riomv 19. 39/652 CUL mw D K51 r/mmvINVENTORS.

BY M M/WW/ 19 of the cylindrical bore. Outward movement of each grippingmember or slip 20 is resisted by one or a plurality of springs 28, 29,which are preferably arranged radially, the inner ends of the springsbeing received within an inner socket in the inner portion of thegripping member 20, the outer ends of the springs bearing against aretaining member or block 31, of elongate form, which includes a centralportion 32 whose outer surface is parallel to the axis of the body 10,and which bears against the inner wall of the well casing C. From theintermediate portion 32 each block or member has an upper tapered guideportion 33 and also a lower tapered guide portion 34 slidable in upperand lower longitudinad body grooves 35 opening into the cylindrical bore19, the grooves 35 running into upper and lower circumferential bodygrooves 36, which, in turn, merge into upper and lower circumferentialrecesses 37 in the body portion 11. Each block has upper and lower stopterminals 38, 39 extending within the upper and lower recesses 37.Outward movement of each retaining block is limited by engagement of theupper terminal 38 with an upper stop flange or ring 40 forming part ofthe main body 11, and also by engagement of the lower terminal 39 with aretaining ring 41 surrounding the lower portion of the body section 11and having an inwardly directed flange 42 disposed under an outer flange43 of the body. The lower retaining ring 41 is held in place by thelower body section 13, which is prevented from being inadvertentlyunthreaded from the main body 11 by a cap screw 44. A similar cap screw44 may also be used to prevent inadvertent unthreading of the uppersection 12 of the body from the main body section 11.

Each gripping member or slip 20 has a longitudinally extending groove45, which is illustrated as being formed centrally thereof, opening tothe exterior of the gripping member, this groove being of a widthconforming to the width of the retaining block 31, thereby providingspaced gripping portions 23 that straddle the retaining block, theretaining block 31, in effect, forming a guide in conjunction with thecylindrical bore 19 for each gripping member during its outward andinward movement in the cylindrical bore. The retaining block 31 alsoserves to prevent turning of each gripping member 20 in its bore 18, sothat the outer wickers or teeth 24 remain oriented in the properdirection, preferably lying in planes normal to the axis of theapparatus A.

One or a plurality of retracting springs 28, 29 may be used. Asillustrated, an outer main spring 28 is disposed in the socket 30 ofeach gripping member with its outer portion adapted to bear against thecentral part 32 of the retaining member 31. An inner auxiliary spring 29is also disposed within the main spring 28, its inner end bearingagainst the base 46 of the gripping member socket 30, and its outer endbearing against the retaining member or block 31. The retaining memberor block functions as a spring seat for the outer ends of the springs,which spring seat is movable radially of the main body 10 of theapparatus, depending upon the inside diameter of the casing C, in whichthe apparatus is to be used. When the apparatus is out of the wellcasing C, the springs 28, 29 will move the retaining block 31 outwardlyto the extent limited by engagement of its terminals 38, 39 with theupper and lower retaining rings 40, 41. However, upon inserting theapparatus in the well casing, the blocks 31 are shifted inwardly of thebody 10 to some extent, possibly compressing the springs to a slightextent, the inner ends of the springs forcing each piston 20 inwardly toits fullest extent.

Following lowering of the apparatus A on the tubular string in the wellcasing to the desired setting point, pressure is imposed on the fluid inthe tubular string and in the central passage 25 of the body, whichmight result from performing a pressuring operation in the well borebelow the point at which the anchor is set. As an example, if the lowerportion of the anchor is attached to a set down type of hook wall packerD, then the setting of the packer against the well casing C will resultin a closing of the annulus between the packer body and the wall of thewell casing. Accordingly, fluid under pressure can be pumped downthrough the apparatus, and such fluid under pressure will act on theinner ends of the pistons 20 to urge them outwardly against the force ofthe springs 28, 29. When the fluid pressure becomes sufficiently great,the gripping members 20 are shifted outwardly until their wickers orteeth 24 are embedded in the wall of the well casing, thereby anchoringthe body to the wall of the well casing. The greater the pressure, thegreater will be the force holding the gripping members 20 anchoredagainst the casing, thereby precluding longitudinal movement of theanchor A in the well casing C. When the pressure is relieved, thesprings 28, 29 will shift the pistons 20 inwardly from engagement withthe well casing, and to their fully retracted position.

By virtue of use of the laterally or radially movable retaining blocks31 the slide along the wall of the well casing C, larger size springs28, 29 can be mounted in the apparatus between each retaining block andthe inner portion of each gripping member 20. The springs 28, 29 can beof a greater length and may be made of metal having greatercross-sections than was heretofore possible. The main spring 28 for eachgripping member 20 is preferably so designed that it may actually exertvery little, if any, spring force when the gripping member is in itsfully retracted position, and it will exert a maximum force when thegripping member has moved outwardly into gripping engagement with thewall of the well casing C, just before the spring 28 would be compressedto its solid height. Thus, the main spring 28 exerts a maximum forcetending to prevent the wickers or teeth 24 of the gripping member fromengaging the wall of the well casing, and thereby requiring a greaterpressure for the same cross-sectional area of gripping member 20 toshift the gripping member outwardly into firm anchoring engagement withthe wall of the well casing.

The aforenoted powerful main springs 28, requiring greater fluidpressures before each gripping member is shifted into anchoringengagement with the well casing, insures that each gripping member willnot be shifted outwardly sufliciently to bring its wickers 24 intocontact with the wall of the well casing during raising or lowering ofthe apparatus through the fluid in the well casing, which actuallydevelops pressure within the body passage. As an example, if the springs28, 29 exert sufficient force as to require at least 200 psi. pressuredifferential to be built up in the body passage 25 before the wickers 24are engaged with the wall of the well casing, such pressures are notreached as a result of merely running the apparatus in the well casingor removing it therefrom. Accordingly, the wickers do not become dull asa result of sliding along the wall of the well casing C during thelowering or elevating of the apparatus A therewithin.

The springs 28, 29 exert the same resisting torce to outward expansionof each gripping member 20 for different inside diameters of the casingC in which the tubing anchor A can be used. With smaller insidediameters of well casing, the retaining blocks 31 are shifted inwardlyof the body 10 to a greater extent; whereas, in large inside diametersof well casing, the retaining blocks 31 move outwardly to a greaterextent, such inward or outward position relative to the body beingpermitted by the compression or elongation of the springs 28, 29, andparticularly by the auxiliary springs 29, which normally exert a muchlesser force than the outer, much heavier main springs 28. Regardless ofthe inside diameter of the well casing C in which the apparatus is used,the springs 28, 29 are compressed to the same extent when its associatedgripping member or slip 20 is shifted into anchoring engagement with thewell casing C. This-is due to the fact that each retaining block 31engages the well casing at all times, regardless of its inside diameter(within the range of use of a particular anchor); and the grippingmember must, therefore, be expanded outwardly to the same position alongthe block to bring its wickers into anchoring engagement with the wallof the well casing. In other words, the gripping member 20 occupies afinal position relative to the retaining block 31 'Which is the same,regardless of the inside diameter of the well casing C. When thetwickers24 firmly grip the well easing, the main springs 28 are preferablycompressed almost to solid height. Thus, with lesser inside diameters ofeasing, each retainer block 31 will be disposed inwardly of the body toa greater extent than with greater inside diameters of easing, so thateach spring 28 may be initially compressed to some extent beforepressure is applied to the gripping member, urging it outwardly.However, the same final pressure is "required to bring the grippingmember into anchoring engagement With the well easing, regardless of itsinside diameter, since the gripping meniber occupies the same finalposition with respect to the retaining block 31. g v

In addition to functioning as movable spring seats,

and spring seats that extend a greater distance from the axis of thebody of the apparatusso that longer and heavier springs 28, 29 can beincorporated in the apparatus A, the retaining blocks .31 also serve ascentering devices or centering vanes tending to prevent the main body 10of the apparatus from leaning against one side of the casing C.Accordingly, greater assurance is bad that the main body 10* will bedisposed in a position coaxial of the Well casing, insuring bettergripping engagement of the slips 20 with the wall of the well casing,with greater ability to resist relatively large forces tending to shiftthe anchor A longitudinally in the well casing C.

After the anchor A has served its purpose, the fluid pressuretherewithin may be relieved, the springs 28, 29 shifting the grippingmembers 26 inwardly away from the well casing, which enables the anchorto be moved in the Well casing to a different setting point or, ifdesired, to be removed entirely from the well casing.

In the form of invention illustrated in FIGS. 1 to 5, inclusive, asingle set of circumferentially spaced gripping members 20 is disclosed.In the form of invention illustrated in FIG. 6, the anchor issubstantially the same as in the form heretofore described, except forthe fact that sets of longitudinally spaced gripping members 20a, 20bare illustrated. The upper set Zita is in staggered relation to thelower set 2%, actually being displaced 90 degrees from the lower set.With this arrangement, each gripping member can have a rather largediameter, which reduces the number of gripping members necessary foranchoring the apparatus against the Wall casing to withstand greatlongitudinally directed hydraulic or other forces, since the hydraulicpressure in the apparatus is acting on each gripping member of muchgreater area. Each gripping member 20 in the other form of the invention(FIGS. 1 to 5) can also be made of a much greater cross-sectional areabecause of the ability to use heavier springs 28, 29, which will alsoreduce the number that are required. The reduction of the number ofgripping members reduces the cost of the apparatus considerably sincefewer parts and machining operations are required to produce thecomplete anchor A.

The inventors claim:

1. In apparatus to be lowered in a well conduit: a body 7 having a fluidpassage and a lateral opening in the body communicating with saidpassage; a gripping member movable laterally in said opening and movableby the pressure of fluid in said passage into gripping engagement withthe well conduit; a retaining member movable laterally on said body andengageable with the well conduit; and spring means engaging saidretaining member and gripping member to urge said gripping memberlaterally r '6 inwardly toward the axis of said body andsaid retainingmember outwardly against the well conduit.

2. In apparatus to be lowered in a well conduit: a body having a fluidpassage and a lateral opening in the body communicating with saidpassage; a gripping member movable laterally in said opening inleakproof relation to the wall of said opening and movable byfthepressure of fluid in said passage into gripping engagement with the wellconduit; a retaining member carried by said body and movable laterallythereof to and fromthe axis of said body; and compression spring meansengaging said retaining member and gripping member to urge said grip.-ping member laterally inwardly toward the axis of said body and saidretaining member outwardly against the well conduit.

3. In apparatus to be lowered in a well conduit: a body having a fluidpassage and a lateral openingi'n the body communicating with saidpassage; a gripping member movable laterally in said opening inleakproof relation to the wall of said opening and movable by thepressure of fluid in said passage into gripping engagement with the wellconduit; a retaining member carried by said body and movable laterallythereof to and from the axis of said body; said gripping member beingslidable along said retaining member inmovi'ng to and from gripping en.-gagement with the well conduit; and a spring between and engaging saidretaining member and gripping member and adapted to be compressedbetween said gripping member andretaining member as said gripping membermoves laterally in said opening toward the conduit string.

4. In apparatus to be lowered in a well conduit: a body having a fluidpassage and a lateral opening in the body communicating with saidpassage; a gripping member movable laterally in said opening and movableby the pressure of fluid in said passage into gripping engagement withthe well conduit; a retaining member movable laterally on said body andengageable with the well conduit; spring means engaging said retainingmember and gripping member to urge said gripping member laterally inwardly toward the axis of said body; and means on said body engageablewith said retaining member to limit its lateral outward movement on saidbody.

5. In apparatus to be lowered in a well conduit: a body having a fluidpassage and a lateral opening in the body communicating with saidpassage; a gripping member movable laterally in said opening and movableby the pressure of fluid in said passage into gripping engagement withthe well conduit; said body having guide means; a retaining memberslidable laterally in said guide means and engageable with the wellconduit; and spring means engaging said retaining member and grippingmember to urge said gripping member laterally inwardly toward the axisof said body and said retaining member outwardly against the wellconduit.

6. In apparatus to be lowered in a well conduit: a body having a fluidpassage and a lateral opening in the body communicating with saidpassage; a gripping member movable laterally in said opening and movableby the pressure of fluid in said passage into gripping engagement withthewell conduit; said body having guide means; a retaining memberslidable laterally in said guide means and engageable with the wellconduit; said gripping member being slidable along said retaining memberin moving to and from gripping engagement with the well conduit; andspring means engaging said retaining member and gripping member to urgesaid gripping member laterally inwardly toward the axis of said body andsaid retaining member outwardly against the well conduit.

7. In apparatus to be lowered in a well conduit: a body having a fluidpassage and a lateral opening in the body communicating with saidpassage; a gripping member movable laterally in said opening and movableby the pressure of fluid in said passage into gripping engagement withthe well conduit; said body and gripping memberv having aligned guideportions; a retaining member in said guide portions and engageable withthe well conduit; said retaining member being slidable laterally alongsaid body guide portion and said guide portion of said gripping memberbeing slidable laterally along said retaining member; and spring meansengaging said retaining member and gripping member to urge said grippingmember laterally inwardly toward the axis of said body and saidretaining member outwardly against the well conduit.

8. In apparatus to be lowered in a well conduit: a body having a fluidpassage and a lateral opening in the body communicating with saidpassage; a gripping member movable laterally in said opening and movableby the pressure of fluid in said passage into gripping engagement withthe well conduit; said body and gripping member having aligned groovesgenerally parallel to the axis of the body; a retaining member in saidaligned grooves and movable laterally in said grooves relative to saidbody and gripping member, said retaining member being engageable withthe well conduit; and spring means engaging said retaining member andgripping member to urge said gripping member laterally inwardly towardthe axis of said body and said retaining member outwardly against thewell conduit.

9. In apparatus to be lowered in a well conduit: a body having a fluidpassage and a lateral opening in the body communicating with saidpassage; a gripping member movable laterally in said opening and movableby the pressure of fluid in said passage into gripping engagement withthe well conduit; said body and gripping member having aligned groovesgenerally parallel to the axis of the body; a retaining member in saidaligned grooves and movable laterally in said grooves relative to saidbody and gripping member, said retaining member being engageable withthe well conduit; and a spring between and engaging said retainingmember and gripping member and adapted to be compressed between saidgripping member and retaining member as said gripping member moveslaterally in said opening toward the conduit string.

10. In apparatus to be lowered in a well conduit: a body having a fluidpassage and a lateral opening in the body communicating with saidpassage; a gripping member movable laterally in said opening and movableby the pressure of fluid in said passage into gripping engagement withthe Well conduit; said body and gripping member having aligned groovesgenerally parallel to the axis of the body; a retaining member in saidaligned grooves and movable laterally in said grooves relative to saidbody and gripping member, said retaining member being engageable withthe well conduit; a spring between and engaging said retaining memberand gripping member and adapted to be compressed between said grippingmember and retaining member as said gripping member moves laterally insaid opening toward the conduit string; and means on said bodyengageable with said retaining member to limit its lateral outwardmovement in said body groove,

References Cited in the file of this patent UNITED STATES PATENTS

1. IN APPARATUS TO BE LOWERED IN A WELL CONDUIT: A BODY HAVING A FLUIDPASSAGE AND A LATERAL OPENING IN THE BODY COMMUNICATING WITH SAIDPASSAGE; A GRIPPING MEMBER MOVABLE LATERALLY IN SAID OPENING AND MOVABLEBY THE PRESSURE OF FLUID IN SAID PASSAGE INTO GRIPPING ENGAGEMENT WITHTHE WELL CONDUIT; A RETAINING MEMBER MOVABLE LATERALLY ON SAID BODY ANDENGAGEABLE WITH THE WELL CONDUIT;